1. Field of the Invention
The assimilation of an adequate quantity of physiologically important heavy metals is essential to the health of both humans and animals. Failure of the body to ingest and absorb the necessary amounts of such metals can lead to improper functioning of the metabolic processes as well as to a variety of diseases and associated symptoms. For example, anemia is correlated with an iron deficiency. Inadequate amounts of zinc may lead to skin conditions, loss of taste, neuropsychiatric symptoms, and in some animals the development of congenital anomalies and even the suppression of growth.
The absorptive cells of the mammalian intestine contain membranes and metal-binding proteins that present an ominous barrier to the transport of essential metal ions from the lumen to the blood. While metal deficiencies are often associated with improper dietary intake, they are also likely to be the result of malabsorption through this barrier. For instance, the infant disease acrodermatitis enteropathica (AE) impedes zinc absorption in the body, leading to death if not timely checked. This invention relates to a novel method of supplementing the diets of humans and animals with essential metals in an assimilable form which compensates for certain absorptive disorders.
2. Description of the Prior Art
Elemental metal and inorganic metallic salts have generally proven to be ineffective dietary amendments, particularly for subjects having intestinal malfunctions. Pharmacological doses of one metal can cause side effects resulting from competition with other metals. Also, the toxicity of these forms often restricts the dosages to suboptimal levels for attaining the desired profile in the organism's system.
More recent attempts to correct for metal deficiencies have concentrated on the use of organometallic compounds. Braun et al. [Europ. J. Pediat. 121: 247-261 (1976)] describes an attempt to treat AE in two children with 20 mg. Zn daily in the form of zinc-DL-aspartate, but with absolutely no clinical improvement. Ashmead et al., U.S. Pat. No. 4,020,158, employs metal proteinates as a feed supplement in which hydrolyzed protein products are chelated with metal ions under carefully controlled reaction conditions. Similarly, in U.S. Pat. No. 4,167,564, N. L. Jensen shows administering to animals essential metals as complexes or chelates with hydrolyzed proteins, wherein the complexes are stabilized by means of a buffer system. M. M. Abdel-Monem, U.S. Pat. No. 4,021,569, teaches zinc supplementation via zinc methionine complex salts.
While there is evidence that metals complexed with protein derivatives are more effectively assimilated than the elemental or inorganic salt forms, the exact mechanism of absorption, particularly as related to competing metals, has never been previously elucidated. Accordingly, there has always been some uncertainty attached to the prescription of proper dosages of supplemental elements.